He played an influential role at the club for six seasons and was a key member of the team that won the domestic double in 2004–05 and three Danish Cups.

Born in Rødovre, Capital Region of Denmark, Retov started his career in the youth teams of Danish club Rishøj Idrætsforening at age 8, where he played together with his friends from school.

[5][3] Retov quickly became a mainstay in the Brøndby team, and formed a successful duo with Morten Wieghorst in central midfield.

However, the club won the Danish Cup – Brøndby's sixth – as Retov scored the decisive 3–2 winning goal in the 85th-minute of the final to beat out Esbjerg fB.

[15][16] However, Hansa Rostock did not manage to challenge for promotion during the 2008–09 season, with only 14 points after 12 matches, which lead to Pagelsdorf being sacked on 11 November.

[18] The season ended with the club in 13th place in the table, two points clear of relegation play-offs, as Retov made two goals in 31 appearances.

In the following season, Retov only made 24 appearances for the club after receiving a seven-game suspension due to headbutting an opponent on 28 March 2010 in a match against FC St.

[24] On 25 July, Retov made his first start for the club in a Superliga fixture against Lyngby Boldklub, a game which Horsens lost 1–0 away.

[32][33] Despite missing out on bronze medals, Retov called the season "fantastic" after the club had only reached promotion to the highest division two years prior.

[36][37] After suffering a groin injury in pre-season,[38][39] he made his first start of the new season on 23 August 2012, in a Europa League qualifier against Portuguese side Sporting CP which ended 1–1.

As his injury continued to irritate, Retov was sidelined during the winter break and parts of the fall due inflammation of the groin.

A dramatic endphase, in which Horsens thought they had scored the 1–0 goal after a towering header by Alexander Juel Andersen, was, however, cleared off the goal-line by Jens Stryger Larsen.

Shortly afterwards, Brøndby's 10 men (following a red card to Brøndby-winger Quincy Antipas) had a quick counter-attack, where Dennis Rommedahl's low cross into the box found Lebogang Phiri who could easily score the 0–1 which meant relegation to the Danish 1st Division (second tier) for Horsens and Retov.

[26] Before relegation, Retov had stated that he would follow the team down a division,[44] which he stayed true to by signing a three-year contract extension on 15 July.

[45] He made his first appearance in the Danish second tier since leaving Køge Boldklub in 2002, on 28 July in a fixture against AB which Horsens won comfortably 4–1.

[26] Before the 2014–15 season, new coach Bo Henriksen decided to appoint Janus Drachmann captain, while Retov acknowledged that he would take a step back and play less, now being 34 years old.

[26] Following the season, in which Horsens only reached a disappointing mid-table finish, Retov was released after having lost his place as a starter for the team.

[57] He debuted for the senior team on 28 April 2004 in an friendly against Scotland, coming on as a late substitute for then Brøndby-teammate Morten Wieghorst as Denmark won 1–0.

The day after head coach Alexander Zorniger was sacked on 18 February 2019, Retov was appointed as caretaker manager of Brøndby with Matthias Jaissle as his assistant.

[62][63] On 5 March 2020, Retov was placed in home quarantine after having met with former Brøndby-player and teammate Thomas Kahlenberg, who had tested positive for SARS-CoV-2 in the early stages of the COVID-19 pandemic in Denmark.